This invention relates to methods and systems for delivering Quality of Service (QoS) on IP packet based connections over a wireless link.
The Internet is evolving to support Quality of Services in addition to the existing Best Effort services. Two service frameworks are being developed by the Internet Engineering Task Force (IETG) to provide guarantees for service quality in IP (Internet Protocol) networks. They are the Integrated Services (IntServ) model, and the Differentiated Services (DiffServ) model.
The IntServ model is based on resource reservation on a per flow or aggregate basis to support applications that require bounded delay and bandwidth. It uses the Resource Reservation Protocol (RSVP) to set up paths and reserve resources for a packet data flow on an end-to-end basis, thereby providing hard QoS guarantees.
The DiffServ model was proposed for implementing scalable service differentiation in the Internet. It classifies and marks IP packets through the setting of the DS/TOS field of each packet""s IP header to give them a particular per hop forwarding behavior on nodes along their paths. The packets are forwarded based on their markings, in other words, they are given certain per hop behavior (PHB). The general QoS parameters considered for packet data are delay, packet error rate, and data rate. In the DiffServ model, these parameters may be implicitly expressed through the values of the DS field.
As wireless networks, and in particularly CDMA networks, evolve to support IP capabilities, they need an effective mechanism for transferring QoS signaling over the air. It would be advantageous if wireless networks could support end-to-end QoS signaling adopted by wire line IP networks. One example of such a mechanism for RSVP signaling has been provided in Applicant""s application Ser. No. 60/153749 filed Sep. 13, 1999. While an effective QoS signaling mechanism is taught, a QoS delivery mechanism for providing the agreed upon QoS is not. Furthermore, no mechanism for delivering DiffServ functionality is provided.
To provide end-to-end QoS management, wireless networks including mobile cellular networks and fixed wireless networks should support the IP service models for QoS management such as the IntServ and/or DiffServ models. However, existing wireless networks such as the cellular IS-136 TDMA networks or the cellular IS-95 CDMA networks do not provide IP services with guaranteed service qualities for customers. Consequently, IP QoS management is a new issue for wireless engineering. There are no readily available solutions for technically supporting such a function in wireless networks.
In the current cdma2000 standards, the MUX and QoS sub-layer adds a 3-bit SRID to the data frame to be sent over the air. On the receiving end, the MUX and QoS function has to recover the SRID and relies on it to determine which appropriate service instance will deal with the data packet. The SRID is generated by a mobile terminal during the registration process and communicated to the base station through an origination message. The base station or network is not responsible for creation of SRID. The existing SRID is not related to any particular IP QoS requirement or data flow. This is because the existing Link Layer in cdma2000 standards is not IP-aware. As a result, the existing cdma2000 standards cannot support specific IP QoS for a specific data flow.
IP QoS management systems and methods are provided which allow wireless networks to allocate radio resources to each service request more efficiently than would be the case where IP QoS management is not available. This advantage comes from the fact that IP QoS management enables wireless networks to perform resource allocation on demand to meet QoS requirements of IP services. From the frequency spectrum efficiency perspective, this is very beneficial to wireless networks as radio frequency spectrum resources are scarce in nature and are a major limiting factor on network capacities.
The present invention provides IP QoS management solutions in wireless networks and, to this end, provides a method and apparatus for IP QoS management.
The invention provides an IP QoS management mechanism for modern wireless networks to guarantee delivery of IP services with the required quality through the networks to customers. In order to realize IP QoS management in wireless networks, the invention provides a layered QoS management architecture which performs the QoS control over the entire communication protocol stack of a wireless network. The architecture consists of two levels of IP QoS management with an adaptation interface between them. These different functional and adapting levels are called, from top to bottom, Upper Layer QoS Management (ULQM), IP QoS adaptation (IQA), and Lower Layer QoS Management (LLQM).
The ULQM is responsible for IP QoS management in the Upper Layers of a wireless network for end-to-end QoS delivery. In contrast, the LLQM takes charge of managing IP QoS in the Link Layer and Physical Layer of the network. To shield the LLQM from burdens caused by coping with application details from the Upper Layers, the IQA plays a role in buffering and adapting the QoS signaling flow from the Upper Layers to prevent it from directly entering into the LLQM without adaptation. Therefore, the IQA allows the ULQM and LLQM to work independently of each other. In addition to this functionality, the IQA also provides a link between the LLQM and the ULQM in the form of a QoS delivery path from the Upper Layers to the Link Layer and Physical Layer of the network to consistently provide an IP QoS management flow over a wireless link.
The IQA sub-layer contains two entities. One is called the IP QoS Adaptation Control Function (IQACF), residing in the control plane of the communication protocol stack and the other is called the IQA Entity (IQAE), residing in the data plane of the stack.
In a preferred embodiment, the invention is incorporated in a cdma2000 wireless system to perform IP QoS management so that the cdma2000 wireless system can deliver IP services with the required QoS to its customers. Preferably, the IQA is inserted as a sub-layer between the Upper Layers and the Link Layer of the system. In the cdma2000 context, the invention provides a mechanism to make the Link Layer be aware of the IP QoS requirement by inserting an IQA sub-layer, and uses a mapping function to generate an SRID based on the IP QoS parameters and endpoints. This way, the desired QoS can be supported by the Link Layer and the Physical Layer via the SRIDxe2x80x94logical channelxe2x80x94physical channel association. Furthermore, the invention provides a method to support dynamic change of QoS both at the mobile terminal and from the network side at the base station. In the event a new QoS request is initiated by the IP application through a change of value in the DS field, the IQAE at the mobile or the base station can detect such a change and initiate a service negotiation process to accommodate the new request. Such a dynamic QoS mechanism is not available in the existing cdma2000 standards.
In a cdma2000 system, the ULQM can be implemented by using the TCP/UDP/IP sub-layer in the Upper Layers of the system. More generally, preferably a standard solution for the realization of the ULQM is employed.
As for the LLQM, however, there are no clearly available solutions specified by the present cdma2000 standard. While a complete LLQM realization would be related to all aspects of the Link Layer including LAC retransmission protocol, request admission control, dynamic resource allocation, handoff management, LAC and MAC signaling, and logical resource to physical resource mapping, such a detailed solution is beyond the scope of this invention. These details can easily be worked out by persons skilled in the art. Rather, the invention provides a high level solution to the problem and gives a methodology for conceptually implementing the LLQM in the Link Layer of a cdma2000 system.
With the IQA sub-layer and the ideas and methodologies provided by the invention to implement the ULQM and LLQM in the Upper Layers and Link Layer of a cdma2000 system, the entire QoS management on the network can be effectively supported. Advantageously, it guarantees end-to-end QoS for delivered IP services across the network. Also, it allows resource utilization of a cdma2000 system to be more efficient than would be the case where IP QoS management is not available. This benefit is gained due to the system being able to allocate its resources on demand by QoS requirements of IP services. This means the system can avoid any over-provisioning of resources and can operate more economically.